# Question #745c2

##### 1 Answer

#### Explanation:

The thing to remember about concentrations expressed in **parts per million** is that they are calculated by looking at the *number of parts* of solute present **for every**

In other words, you're looking for the number of grams of solute present in

A **for every**

Now, you know that your solution must have a concentration of **ppm** and that the mass of the solution is equal to

Your goal here will be to use the solution's parts per million concentration as a **conversion factor** to calculate the number of grams of sodium chloride, your solute, needed to make this solution.

#1.0 color(red)(cancel(color(black)("g solution"))) * overbrace("100.0 g NaCl"/(10^6color(red)(cancel(color(black)("g solution")))))^(color(blue)("= 100.0 ppm NaCl solution")) = color(darkgreen)(ul(color(black)(1.0 * 10^(-4)color(white)(.)"g NaCl")))#

The answer is rounded to two **sig figs**, the number of sig figs you have for the mass of the solution.